search
HomeDatabaseMysql TutorialWhat are MySQL Binlog logs and master-slave replication?

1. Introduction to Binlog log

Binlog is the abbreviation of Binary log, that is, binary log. The three main functions of Binlog include converting random IO into sequential IO for persistence, realizing master-slave replication and supporting data recovery. This article focuses on issues related to master-slave replication.

Binlog log consists of an index file and many log files. Each log file consists of a magic number and an event. Each log file ends with a Rotate type event.

What are MySQL Binlog logs and master-slave replication?

For each event, it can be divided into two parts: event header and event body:

The event header The structure is as follows:

What are MySQL Binlog logs and master-slave replication?

The structure of the event body includes two parts: fixed size and variable size.

As for the format of Binlog log, you can have a simple understanding. Interested students can study in depth.

2. Master-slave replication

2.1 Master-slave replication process

What are MySQL Binlog logs and master-slave replication?

MySQL master-slave replication process is roughly as follows:

  • The main library synchronizes its own Binlog log to the slave library

  • The IO thread of the slave library writes the Binlog log content to the Relay Log

  • Get the Relay Log from the SQL thread of the library and play it back in the database

2.2 GTID

GTID refers to the global Transaction flag, used to mark master-slave synchronization.

When the master node submits a transaction, a GTID will be generated and recorded in the Binlog log. When the IO thread of the slave library reads the Binlog log, it will store it in its own Relaylog and set this value to gtid_next, which is the next GTID to be read. When reading this gtid_next from the library, it will compare Whether there is this GTID in your Binlog log:

  • If there is this record, it means that the transaction with this GTID has been executed and can be ignored (idempotent).

  • If there is no such record, the slave will execute the GTID transaction and record it in its own Binlog log.

2.3 Replication model

  • Asynchronous replication: master pushes the Binlog log to the slave, and the master does not need to wait until the slave After successfully updating the data to the Relay log, the main database can directly submit the transaction. This mode sacrifices data consistency.

  • Synchronous replication: Every time the user operates, it must be ensured that both the Master and Slave are executed successfully before returning it to the user.

  • Semi-synchronous replication: does not require the Slave to execute successfully, but can notify the Master to return after successfully receiving the Master log.

What are MySQL Binlog logs and master-slave replication?

2.4 MGR mode

Distributed consensus algorithm Paxos. A database cluster consists of at least 3 or more nodes. Transaction submission must be approved by more than half of the nodes before it can be submitted. Multi-write mode is supported.

MGR is a share-nothing replication solution, implemented based on the distributed paxos protocol. Each instance has an independent complete copy of the data. The cluster automatically checks node information and synchronizes data. Both single-master mode and multi-master mode are provided. The single-master mode can automatically select the master after the main database goes down. All writes are performed on the master node. The multi-master mode supports multi-node writing. The cluster provides fault tolerance. As long as most nodes are running normally, the cluster can provide services normally.

2.5 Parallel playback

Transaction playback is the process of executing Relay Log from the SQL thread of the library. Parallel playback is to improve the efficiency of this process and perform transactions that can be carried out in parallel at the same time.

  • Parallel playback based on logical clock

Because MySQL's own transactions have ACID characteristics, the transactions from the master database to the slave database are synchronized. As long as the logical timing of their execution overlaps, the two transactions can be safely played back in parallel.

  • Parallel playback based on writeSet

Store the transaction set regarding a specific data block area within a certain period of time in a HashMap. Conflicts do not occur between transactions within the same group or between transactions with overlapping logical clocks, and otherwise it is impossible to determine whether a conflict exists.

The above is the detailed content of What are MySQL Binlog logs and master-slave replication?. For more information, please follow other related articles on the PHP Chinese website!

Statement
This article is reproduced at:亿速云. If there is any infringement, please contact admin@php.cn delete
图文详解mysql架构原理图文详解mysql架构原理May 17, 2022 pm 05:54 PM

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于架构原理的相关内容,MySQL Server架构自顶向下大致可以分网络连接层、服务层、存储引擎层和系统文件层,下面一起来看一下,希望对大家有帮助。

mysql怎么替换换行符mysql怎么替换换行符Apr 18, 2022 pm 03:14 PM

在mysql中,可以利用char()和REPLACE()函数来替换换行符;REPLACE()函数可以用新字符串替换列中的换行符,而换行符可使用“char(13)”来表示,语法为“replace(字段名,char(13),'新字符串') ”。

mysql的msi与zip版本有什么区别mysql的msi与zip版本有什么区别May 16, 2022 pm 04:33 PM

mysql的msi与zip版本的区别:1、zip包含的安装程序是一种主动安装,而msi包含的是被installer所用的安装文件以提交请求的方式安装;2、zip是一种数据压缩和文档存储的文件格式,msi是微软格式的安装包。

mysql怎么去掉第一个字符mysql怎么去掉第一个字符May 19, 2022 am 10:21 AM

方法:1、利用right函数,语法为“update 表名 set 指定字段 = right(指定字段, length(指定字段)-1)...”;2、利用substring函数,语法为“select substring(指定字段,2)..”。

mysql怎么将varchar转换为int类型mysql怎么将varchar转换为int类型May 12, 2022 pm 04:51 PM

转换方法:1、利用cast函数,语法“select * from 表名 order by cast(字段名 as SIGNED)”;2、利用“select * from 表名 order by CONVERT(字段名,SIGNED)”语句。

MySQL复制技术之异步复制和半同步复制MySQL复制技术之异步复制和半同步复制Apr 25, 2022 pm 07:21 PM

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于MySQL复制技术的相关问题,包括了异步复制、半同步复制等等内容,下面一起来看一下,希望对大家有帮助。

带你把MySQL索引吃透了带你把MySQL索引吃透了Apr 22, 2022 am 11:48 AM

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了mysql高级篇的一些问题,包括了索引是什么、索引底层实现等等问题,下面一起来看一下,希望对大家有帮助。

mysql怎么判断是否是数字类型mysql怎么判断是否是数字类型May 16, 2022 am 10:09 AM

在mysql中,可以利用REGEXP运算符判断数据是否是数字类型,语法为“String REGEXP '[^0-9.]'”;该运算符是正则表达式的缩写,若数据字符中含有数字时,返回的结果是true,反之返回的结果是false。

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software